Auto merge of #5130 - JohnTitor:split-up-index-slice, r=flip1995

Split up `indexing_slicing` ui test

Closes #2038

Now all the stderrs are less than 200 lines 🎉

changelog: none

clippy_dev/src/stderr_length_check.rs

@@ -7,7 +7,7 @@ use std::io::prelude::*;
 // The maximum length allowed for stderr files.
 //
 // We limit this because small files are easier to deal with than bigger files.
-const LIMIT: usize = 220;
+const LIMIT: usize = 200;
 
 pub fn check() {
     let stderr_files = stderr_files();

tests/ui/indexing_slicing_index.rs

@@ -0,0 +1,31 @@
+#![warn(clippy::indexing_slicing)]
+// We also check the out_of_bounds_indexing lint here, because it lints similar things and
+// we want to avoid false positives.
+#![warn(clippy::out_of_bounds_indexing)]
+#![allow(clippy::no_effect, clippy::unnecessary_operation)]
+
+fn main() {
+    let x = [1, 2, 3, 4];
+    let index: usize = 1;
+    x[index];
+    x[4]; // Ok, let rustc's `const_err` lint handle `usize` indexing on arrays.
+    x[1 << 3]; // Ok, let rustc's `const_err` lint handle `usize` indexing on arrays.
+
+    x[0]; // Ok, should not produce stderr.
+    x[3]; // Ok, should not produce stderr.
+
+    let y = &x;
+    y[0];
+
+    let v = vec![0; 5];
+    v[0];
+    v[10];
+    v[1 << 3];
+
+    const N: usize = 15; // Out of bounds
+    const M: usize = 3; // In bounds
+    x[N]; // Ok, let rustc's `const_err` lint handle `usize` indexing on arrays.
+    x[M]; // Ok, should not produce stderr.
+    v[N];
+    v[M];
+}

tests/ui/indexing_slicing_index.stderr

@@ -0,0 +1,79 @@
+error: index out of bounds: the len is 4 but the index is 4
+  --> $DIR/indexing_slicing_index.rs:11:5
+   |
+LL |     x[4]; // Ok, let rustc's `const_err` lint handle `usize` indexing on arrays.
+   |     ^^^^
+   |
+   = note: `#[deny(const_err)]` on by default
+
+error: index out of bounds: the len is 4 but the index is 8
+  --> $DIR/indexing_slicing_index.rs:12:5
+   |
+LL |     x[1 << 3]; // Ok, let rustc's `const_err` lint handle `usize` indexing on arrays.
+   |     ^^^^^^^^^
+
+error: index out of bounds: the len is 4 but the index is 15
+  --> $DIR/indexing_slicing_index.rs:27:5
+   |
+LL |     x[N]; // Ok, let rustc's `const_err` lint handle `usize` indexing on arrays.
+   |     ^^^^
+
+error: indexing may panic.
+  --> $DIR/indexing_slicing_index.rs:10:5
+   |
+LL |     x[index];
+   |     ^^^^^^^^
+   |
+   = note: `-D clippy::indexing-slicing` implied by `-D warnings`
+   = help: Consider using `.get(n)` or `.get_mut(n)` instead
+
+error: indexing may panic.
+  --> $DIR/indexing_slicing_index.rs:18:5
+   |
+LL |     y[0];
+   |     ^^^^
+   |
+   = help: Consider using `.get(n)` or `.get_mut(n)` instead
+
+error: indexing may panic.
+  --> $DIR/indexing_slicing_index.rs:21:5
+   |
+LL |     v[0];
+   |     ^^^^
+   |
+   = help: Consider using `.get(n)` or `.get_mut(n)` instead
+
+error: indexing may panic.
+  --> $DIR/indexing_slicing_index.rs:22:5
+   |
+LL |     v[10];
+   |     ^^^^^
+   |
+   = help: Consider using `.get(n)` or `.get_mut(n)` instead
+
+error: indexing may panic.
+  --> $DIR/indexing_slicing_index.rs:23:5
+   |
+LL |     v[1 << 3];
+   |     ^^^^^^^^^
+   |
+   = help: Consider using `.get(n)` or `.get_mut(n)` instead
+
+error: indexing may panic.
+  --> $DIR/indexing_slicing_index.rs:29:5
+   |
+LL |     v[N];
+   |     ^^^^
+   |
+   = help: Consider using `.get(n)` or `.get_mut(n)` instead
+
+error: indexing may panic.
+  --> $DIR/indexing_slicing_index.rs:30:5
+   |
+LL |     v[M];
+   |     ^^^^
+   |
+   = help: Consider using `.get(n)` or `.get_mut(n)` instead
+
+error: aborting due to 10 previous errors
+

tests/ui/indexing_slicing.rs → tests/ui/indexing_slicing_slice.rs

@@ -1,4 +1,3 @@
-#![feature(plugin)]
 #![warn(clippy::indexing_slicing)]
 // We also check the out_of_bounds_indexing lint here, because it lints similar things and
 // we want to avoid false positives.
@@ -10,49 +9,29 @@ fn main() {
     let index: usize = 1;
     let index_from: usize = 2;
     let index_to: usize = 3;
-    x[index];
     &x[index..];
     &x[..index];
     &x[index_from..index_to];
     &x[index_from..][..index_to]; // Two lint reports, one for [index_from..] and another for [..index_to].
-    x[4]; // Ok, let rustc's `const_err` lint handle `usize` indexing on arrays.
-    x[1 << 3]; // Ok, let rustc's `const_err` lint handle `usize` indexing on arrays.
     &x[5..][..10]; // Two lint reports, one for out of bounds [5..] and another for slicing [..10].
     &x[0..][..3];
     &x[1..][..5];
 
     &x[0..].get(..3); // Ok, should not produce stderr.
-    x[0]; // Ok, should not produce stderr.
-    x[3]; // Ok, should not produce stderr.
     &x[0..3]; // Ok, should not produce stderr.
 
     let y = &x;
-    y[0];
     &y[1..2];
     &y[0..=4];
     &y[..=4];
 
     &y[..]; // Ok, should not produce stderr.
 
     let v = vec![0; 5];
-    v[0];
-    v[10];
-    v[1 << 3];
     &v[10..100];
     &x[10..][..100]; // Two lint reports, one for [10..] and another for [..100].
     &v[10..];
     &v[..100];
 
     &v[..]; // Ok, should not produce stderr.
-
-    //
-    // Continue tests at end function to minimize the changes to this file's corresponding stderr.
-    //
-
-    const N: usize = 15; // Out of bounds
-    const M: usize = 3; // In bounds
-    x[N]; // Ok, let rustc's `const_err` lint handle `usize` indexing on arrays.
-    x[M]; // Ok, should not produce stderr.
-    v[N];
-    v[M];
 }